Crystallized hybrid solid having a three-dimensional DMOF-1-N3 organic-inorganic matrix and method for preparing the same

ABSTRACT

A crystallized hybrid solid with an organic-inorganic matrix, of three-dimensional structure, containing an inorganic network of zinc-based metal centers connected to one another by organic ligands constituted by the entities —O 2 C—C 6 H 3 —N 3 —CO 2 — and C 6 H 12 N 2 . Said solid is called DMOF-1-N 3 , and has Zn 2 (—O 2 C—C 6 H 3 —N 3 —CO 2 —) 2 (C 6 H 12 N 2 ) for its base pattern.

TECHNICAL FIELD OF THE INVENTION

This invention relates to a new crystallized hybrid solid with an organic-inorganic matrix, of three-dimensional structure, and to its process for preparation starting from the DMOF-1-NH₂ crystallized hybrid solid with an organic-inorganic matrix that is already described in the literature. Said new solid, object of this invention, carries one azide group and is called DMOF-1-N₃ in the description below. Said DMOF-1-N₃ solid has a crystalline structure that is identical to that of the DMOF-1-N₂ solid with which it is obtained by a post-synthesis functionalization method. Said DMOF-1-N₃ solid is advantageously used in applications as catalyst or adsorbent or else as an intermediate product for obtaining functionalized crystallized hybrid solids with an organic-inorganic matrix.

STATE OF THE ART

The modification of materials by functionalization is a stage that is often necessary for the production of solids that have the properties that are suitable for a given application. Actually, it may be desirable to improve the physico-chemical properties of a material by modifying its surface, for example, so that the new properties that are obtained after modifications are more suitable for separation or catalysis applications.

One of the means that is commonly used for modifying the surface of a material consists in reacting the functional groups that are initially present on its surface by entities that have the groups that are desired for the application being considered. The groups that are present on the surface of a material can be hydroxyl groups (—OH) or any other group (—NH₂ or —NH— amine, for example) that it is desired to modify so as to orient the chemical reactivity of the surface of the material. The reagents that are used will have the functionalities that are necessary for reacting with the groups that are initially present on the surface of the material, and the result of the reaction will be a new chemical group that has the desired reactivity. An example of such a transformation consists in reacting the hydroxyl groups of the surface of a silica by a silane that carries one amine group (D. Brunel, Microporous and Mesoporous Materials, 1999, 27, 329-344). Thus, the hydroxyl group is transformed into an amine group that is more capable of catalyzing basic reactions or of collecting CO₂, for example. This methodology can be applied to any material that initially has reactive groups. These materials can be oxides, zeolites, or else organic/inorganic hybrid materials, also called coordination polymers.

These coordination polymers, of which the first were described in the 1960's, are the subject of a growing number of publications. Actually, the effervescence around these materials made it possible to achieve an advanced structural diversity in a short time (Férey, G., l'actualité chimique [Chemical Issues], January 2007, No. 304). Conceptually, the porous hybrid solids with an organic-inorganic mixed matrix are quite similar to porous solids with inorganic skeletons. Like the latter, they combine chemical entities by giving rise to porosity. The primary difference resides in the nature of these entities. This difference is particularly advantageous and is at the origin of all of the versatility of this category of hybrid solids. Actually, the pore size becomes, by using organic ligands, adjustable by means of the length of the carbon-containing chain of said organic ligands. The framework, which in the case of inorganic porous materials can only accept some elements (Si, Al, Ge, Ga, optionally Zn), can, in this case, collect all of the cations except for the alkalines. For the preparation of these hybrid materials, no specific structuring agent is required; the solvent performs this action by itself.

It therefore clearly appears that this family of hybrid materials makes possible a multiplicity of structures and consequently comprises solids that are finely adapted to the applications that are intended for them.

The coordination polymers comprise at least two elements that are called connectors and ligands whose orientation and whose number of connecting sites are decisive in the structure of the hybrid material. An immense variety of hybrid materials is born, as was already specified, from the diversity of these ligands and connectors.

Ligand refers to the organic part of the hybrid material. These ligands are, most often, di- or tri-carboxylates or derivatives of pyridine. Some organic ligands that are frequently encountered are shown below: bdc=benzene-1,4-dicarboxylate, btc=benzene-1,3,5-tricarboxylate, ndc=naphthalene-2,6-dicarboxylate, bpy=4,4′-bipyridine, hfipbb=4,4′-(hexafluoroisopropylidene)-bisbenzoate, cyclam=1,4,8,11-tetraazacyclotetradecane.

Connector refers to the inorganic entity of the hybrid material. It may involve a single cation, a dimer, trimer or tetramer, or else a chain or a plane.

Within the framework of this invention, the ligands that are used are 2-amino-terephthalic acid (NH₂-bdc) and 1,4-diazabicyclo[2.2.2]octane (DABCO). The inorganic entity that performs the role of connector is zinc.

The teams of Yaghi and Férey thus described a large number of new hybrid materials (series of MOF—“Metal Organic Framework”—and series of MIL—“Materials of l'Institut Lavoisier [Lavoisier Institute]”—respectively). Numerous other teams followed this path, and today, the number of new hybrid materials described is expanding rapidly. Most often, the purpose of the studies is to develop ordered structures, having extremely large pore volumes, good thermal stability, and adjustable chemical functionalities.

For example, Yaghi et al. describe a series of boron-based structures in the patent application U.S. 2006/0154807 and indicate their advantage in the field of gas storage. The patent U.S. Pat. No. 7,202,385 discloses a particularly complete summary of the structures that are described in the literature and perfectly illustrates the multitude of materials already existing as of this time.

The preparation of the organic-inorganic hybrid materials that have a reactive organic group (grafted MOF) can be implemented by two primary paths: the functionalization by self-assembly and the functionalization by post-modification. The functionalization by self-assembly is implemented by presenting an organic ligand that has the desired reactive group (graft) and an inorganic compound that has the role of connector. This method of functionalization is often difficult to implement because of problems linked to the solubilization and the reactivity of functionalized ligands. In particular, the ligands that carry an —OH, —COOH or —NH₂ group run the risk of interacting with the inorganic compound (connector) then leading to non-isostructural solids with non-grafted reference MOF. The functionalization by post-modification is an advantageous alternative method that does not have the limits of functionalization by self-assembly. The functionalization by post-modification consists in directly modifying the organic group of at least one type of ligand that is present in the MOF by a chemical reaction (grafting), more specifically in substituting the initial organic group by an organic group whose reactivity is preferred for a subsequent application. This method assumes the presence on the initial MOF of an organic group that is accessible and reactive for grafting. In literature, the organic-inorganic hybrid materials that carry a ligand with an —NH₂ amino group, such as DMOF-1-NH₂ (Z. Q. Wang; K. K. Tanabe, S. M. Cohen, Inorganic Chemistry, 2009, 48, 296-306), are described as good substrates for the grafting of numerous groups, in particular aldehydes, isocyanates, and acid anhydrides.

DESCRIPTION OF THE INVENTION

This invention has as its object a new crystallized hybrid solid with an organic-inorganic matrix that has a three-dimensional structure. This new solid is called DMOF-1-N₃. It contains an inorganic network of zinc-based metal centers that are connected to one another by organic ligands that consist of the —O₂C—C₆H₃—N₃—CO₂— and C₆H₁₂N₂ entities.

The DMOF-1-N₃ crystallized hybrid solid according to the invention has an X-ray diffraction diagram that includes at least the lines that are inscribed in Table 1. This diffraction diagram is obtained by radiocrystallographic analysis by means of a diffractometer by using the conventional powder method with Kα1 copper radiation (λ=1.5406 Å). Starting from the positions of diffraction peaks shown by the angle 2θ, the characteristic reticular equidistances d_(hkl) of the sample are calculated by applying Bragg's equation. The measuring error Δ(d_(hkl)) to d_(hkl) is calculated using Bragg's equation based on the absolute error Δ(2θ) that is assigned to the measurement of 2θ. An absolute error of Δ(2θ) that is equal to ±0.02° is commonly allowed. The relative intensity I/I_(o) assigned to each d_(hkl) value is measured according to the height of the corresponding diffraction peak. The X-ray diffraction diagram of the DMOF-1-N₃ crystallized hybrid solid according to the invention comprises at least the lines with the values of d_(hkl) given in Table 1. In the d_(hkl) column, the mean values of the inter-reticular distances are indicated in angstroms (Å). Each of these values is to be affected by the measuring error Δ(d_(hkl)) encompassed between ±0.3 Å and ±0.01 Å.

TABLE 1 Mean Values of d_(hkl) and Relative Intensities Measured on an X-Ray Diffraction Diagram of the DMOF-1-N₃ Crystallized Hybrid Solid. 2 Thêta (°) d_(hkl) (Å) I/I₀ 8.152 10.837643 F 9.19 9.615264 mf 11.538 7.663371 mf 12.296 7.192531 mf 14.77 5.992845 ff 16.345 5.418821 FF 18.29 4.846741 f 18.44 4.807632 ff 18.782 4.720763 f 20.19 4.394638 ff 20.504 4.327992 ff 21.806 4.072553 ff 23.195 3.831685 ff 24.623 3.612547 f 24.737 3.596266 ff 24.996 3.559468 ff 25.978 3.427163 ff 26.086 3.413252 ff 26.333 3.381744 ff 27.609 3.228232 ff 27.813 3.205088 ff 29.029 3.0735 f 29.698 3.005821 ff 29.793 2.996423 ff 30.201 2.956894 ff 30.938 2.888069 ff 31.15 2.868907 ff 32.046 2.790679 ff 32.428 2.758663 ff 33.035 2.709411 ff 33.492 2.673413 ff 34.082 2.628514 ff 34.36 2.607855 ff 35.102 2.554457 ff 35.184 2.548681 ff 35.373 2.535482 ff 36.361 2.468819 ff 36.52 2.458421 ff where FF = Very High; F = High; m = Medium; mf = Medium Low; f = Low; and ff = Very Low. The relative intensity I/I_(o) is provided relative to a relative intensity scale where a value of 100 is assigned to the most intense line of the X-ray diffraction diagram: ff < 15; 15 ≦ f < 30; 30 ≦ mf < 50; 50 ≦ m < 65; 65 ≦ F < 85; and FF ≧ 85.

The DMOF-1-N₃ crystallized hybrid solid according to the invention has a crystalline structure with a base or topology that is characterized by its X-diffraction diagram provided by FIG. 1. The crystalline structure of the DMOF-1-N₃ crystallized hybrid solid according to the invention is identical to the one that is exhibited by the DMOF-1-NH₂ crystallized hybrid solid that is described in the literature (Z. Q. Wang; K. K. Tanabe, S. M. Cohen, Inorganic Chemistry, 2009, 48, 296-306), and from which said DMOF-1-N₃ solid is obtained, in accordance with the process for preparation described farther down in this description.

The DMOF-1-N₃ crystallized hybrid solid according to the invention is indexed in a quadratic system of the P4/m space group with, as mesh parameters, a=b=10.837 Å; c=9.614 Å, and alpha=beta=gamma=90°, with these definitions (quadratic system, space group and mesh parameters) being well known to one skilled in the art.

The DMOF-1-N₃ crystallized hybrid solid according to the invention has a three-dimensional structure in which the inorganic network that is formed by Zn²⁺-cation-based metal centers that perform the role of connectors are linked together by deprotonated terephthalic ligands (—O₂C—C₆H₃—N₃—CO₂—) that carry an N₃ azide group on the aromatic cycle and ligands that consist of 1,4-diazabicyclo[2.2.2]octane (DABCO of empirical formula C₆H₁₂N₂). An essential characteristic of the DMOF-1-N₃ crystallized hybrid solid according to the invention resides in the presence of the azide group on the aromatic cycle of each of the deprotonated terephthalic ligands, more specifically called 2-azido-terephthalate ligands (denoted N₃-bdc). The structure that is obtained, identical to that of DMOF-1-NH₂, is three-dimensional. The zinc dimers are connected to one another by deprotonated terephthalic ligands that form square grids (by combination of 4 Zn dimers and 4 N₃-bdc ligands), which lead to a 3D structure by the superposition of these grids by the columns of DABCO ligands. Each Zn atom is therefore pentacoordinated: each zinc atom is surrounded by four oxygen atoms obtained from 4 N₃-bdc ligands that are located in equatorial position and a nitrogen atom that is obtained from a DABCO ligand that is located in apical position. An N₃-bdc ligand is connected to 4 zinc atoms. A DABCO ligand is connected to 2 zinc atoms. The N₃-bdc ligands occupy the equatorial positions while the DABCO ligands connect the zinc atoms in apical position.

The DMOF-1-N₃ crystallized hybrid solid according to the invention thus has a chemical composition that has Zn₂(—O₂C—C₆H₃—N₃—CO₂—)₂(C₆H₁₂N₂) for its base pattern. This pattern is repeated n times, with the value of n based on the crystallinity of said solid.

The DMOF-1-N₃ crystallized hybrid solid according to the invention has also been characterized by Fourier Transform Infrared (FT-IR) spectroscopy and by ¹H NMR in such a way as to verify the presence of the azide group on each of the terephthalate ligands. Thus, the spectrum that is obtained by FT-IR has a characteristic band of the azide group at 2123 cm⁻¹. The ¹H-NMR analysis is implemented on a sample of said DMOF-1-N₃ hybrid solid according to the invention, after digestion and total dissolution of said sample in a DCl/D₂O/DMSO-d₆ deuterated mixture according to an operating mode described in the literature (Z. Q. Wang, S. M. Cohen, Journal of the American Chemical Society, 2007, 129, 12368-12369). The ¹H-NMR analysis confirms the presence of the N₃ azide group on the aromatic cycle of the deprotonated terephthalic ligand: δ=7.74-7.85 ppm, m, 3H, ArH. The 3 protons leading to the detection of the multiplet correspond to the 3 protons carried by the aromatic cycle of the 2-azido-terephthalate (N₃-bdc) ligand.

This invention also has as its object a process for the preparation of the DMOF-1-N₃ crystallized hybrid solid. Said DMOF-1-N₃ solid is prepared from the DMOF-1-NH₂ crystallized hybrid solid that is described in the literature (Z. Q. Wang; K. K. Tanabe, S. M. Cohen, Inorganic Chemistry, 2009, 48, 296-306). Said DMOF-1-NH₂ solid has a three-dimensional structure with an inorganic network that is formed by Zn²⁺-cation-based metal centers that perform the role of connectors linked together by deprotonated terephthalic ligands that carry an —NH₂ amine group on the aromatic cycle (denoted NH₂-bdc ligands) and ligands that consist of 1,4-diazabicyclo[2.2.2]octane (DABCO). A method for preparation of said DMOF-1-NH₂ solid is described in the literature (Z. Q. Wang; K. K. Tanabe, S. M. Cohen, Inorganic Chemistry, 2009, 48, 296-306. The process for preparation of the invention makes possible the substitution of the —NH₂ amine group that is present in the DMOF-1-NH₂ solid by the N₃ azide group. The process for preparation according to the invention comprises at least the following stages:

i/ Introduction, into a polar solvent S, of at least said DMOF-1-NH₂ crystallized hybrid solid, at least one organic compound Q that contains an N₃ azide group, and at least one intermediate reagent R that contains an NO₂ nitrite group in a proportion such that the reaction mixture has the following molar composition: 1 DMOF-1-NH₂:3-12 R:1-9 Q:100-400 S

ii/ Reaction of said reaction mixture at a temperature of between 0 and 100° C. for a period of between 1 and 24 hours to obtain said DMOF-1-N₃ crystallized hybrid solid,

iii/ Filtration, and then washing of said DMOF-1-N₃ crystallized hybrid solid,

iv/ Drying of said DMOF-1-N₃ crystallized hybrid solid.

In accordance with said stage i) of said process for the preparation of the DMOF-1-N₃ crystallized hybrid solid according to the invention, said DMOF-1-NH₂ crystallized hybrid solid is dried in advance before being introduced into said polar solvent. The drying of said DMOF-1-NH₂ crystallized hybrid solid is advantageously implemented at a temperature of between 20 and 100° C. for a period of between 1 and 24 hours, very advantageously for a period of approximately 12 hours. The drying is done in air or under vacuum, in a preferred manner under vacuum.

In accordance with said stage i) of the process for preparation according to the invention, said organic compound Q that contains an N₃ azide group is advantageously selected from among trimethylsilyl azide (TMS-N₃, (CH₃)₃SiN₃), triflyl azide (TfN₃, where Tf=CF₃SO₂), p-tosyl azide (TsN₃ or 4-methylbenzenesulfonyl azide of formula C₆H₄(CH₃)SO₂N₃), and sodium azide (NaN₃). In a preferred manner, said organic compound Q that contains an N₃ group is trimethylsilyl azide (TMS-N₃).

In accordance with said stage i) of the process for preparation according to the invention, said intermediate reagent R that contains an NO₂ nitrite group is advantageously selected from among alkaline reagents such as sodium nitrite (NaNO₂) and calcium nitrite (Ca(NO₂)₂), metal reagents, and alkoxy-type reagents such as tert-butyl-nitrite (tBuONO, (CH₃)₃CONO). In a very preferred manner, said intermediate reagent R that contains an NO₂ nitrite group is tert-butyl-nitrite (tBuONO). Said intermediate reagent R that contains an NO₂ nitrite group ensures the formation of a diazonium salt that next reacts with the organic compound Q.

The polar solvent S that is used in said stage i) of the process for preparation according to the invention is preferably volatile. It is very advantageously selected from among tetrahydrofuran (THF) and acetonitrile.

In accordance with said stage i) of the process for preparation according to the invention, the reaction mixture preferably has the following molar composition: 1 DMOF-1-NH₂:5-7 R:5-8 Q:100-200 S

Said reaction stage in accordance with said stage ii) of the process for preparation according to the invention is preferably implemented at a temperature of between 0 and 60° C., and even more preferably at ambient temperature. The reaction mixture is stirred using a magnetic stirrer. The reaction period is between 1 and 24 hours, preferably between 5 and 15 hours, and most often approximately 12 hours. The solid that is obtained at the end of said stage ii) is a DMOF-1-N₃ crystallized hybrid solid that has an X-ray diffraction diagram that includes at least the lines inscribed in Table 1.

According to said stage iii) of the process for preparation according to the invention, said DMOF-1-N₃ crystallized hybrid solid that is obtained at the end of said stage ii) is filtered and then washed with suitable solvents. The washing of said DMOF-1-N₃ solid is preferably implemented by a first washing sequence by means of polar solvents, for example THF, followed by a second washing sequence by means of volatile solvents, for example dichloromethane. The washing stage of said DMOF-1-N₃ crystallized hybrid solid is initiated, for example, by implementing 3 sequences of washing with THF followed by 3 sequences of washing with CH₂Cl₂ dichloromethane.

In accordance with said stage iv) of the process for preparation according to the invention, said DMOF-1-N₃ crystallized hybrid solid is dried. The drying is done in air or under vacuum between 20° C. and 100° C. In a preferred manner, the drying is done at ambient temperature under vacuum for a period that varies between 1 and 24 hours, most often approximately 12 hours.

In accordance with the process for preparation according to the invention, the DABCO ligands are non-reactive ligands: they do not compete with the NH₂-bdc ligands, and they do not react with said organic compound Q that contains said N₃ group.

The solid that is obtained at the end of stage iv) is identified as being the DMOF-1-N₃ crystallized hybrid solid according to the invention. The analyses that are implemented on the solid that is obtained at the end of the process for preparation according to the invention demonstrate the effectiveness of the treatment by post-modification. In particular, the analysis that is implemented on the DMOF-1-N₃ crystallized hybrid solid by XRD demonstrates that the treatment of functionalization by post-modification that makes it possible to substitute the —NH₂ amino group by the —N₃ azide group does not affect the structure and the crystallinity of the solid. The FT-IR analysis reveals the presence of the —N₃ azide group on each of the terephthalate ligands in the DMOF-1-N₃ solid. The ¹H-NMR analysis confirms the presence of the —N₃ azide group on each of the terephthalate ligands in the DMOF-1-N₃ solid and makes it possible to estimate the rate of modification of the amino groups into N₃ azide groups. In accordance with the process for preparation according to the invention, this rate of modification is very high, i.e., at least equal to 95%, preferably at least equal to 98%. The rate of modification is calculated by quantifying the decrease in the relative area of the signals of aromatic protons of the DMOF-1-NH₂ form relative to those of the DMOF-1-N₃ form. The ¹H-NMR spectrum of the DMOF-1-N₃ solid according to the invention has new signals that are linked to the appearance of an integral multiplet for 3 protons, which correspond to the 3 protons that are carried by the aromatic cycle of the 2-azido-terephthalate (N₃-bdc) ligand.

EXAMPLES

The DMOF-1-NH₂ and DMOF-1-N₃ crystallized hybrid solids that are obtained at the end of the implementation of the preparation protocols illustrated by the following Examples 1 and 2 have been analyzed by X-ray diffraction, by Fourier Transform Infrared (FT-IR) spectroscopy, and by nuclear magnetic resonance of hydrogen (¹H NMR).

The X-ray diffraction diagrams are obtained by radiocrystallographic analysis by using the standard powder method by means of a Bruker D5005 diffractometer (CuKα₁₊₂=0.15418 nm) that is equipped with a graphite curved rear monochromator and a scintillation detector. The analyses of the solids have been recorded with the Debye-Scherrer method from 3 to 80° (2θ) with a pitch of 0.02° for 8 seconds.

The infrared analyses are done using KBr pellets on a Bruker Vector 22 FT-IR device with a useful operating range of: 4,000-400 cm⁻¹.

The nuclear magnetic resonance spectra in solution are obtained using a Bruker Avance 250 NMR spectrometer (5.87 T, 250 MHz for 1H).

Example 1 Preparation of the DMOF-1-NH₂ Crystallized Hybrid Solid

0.781 g of Zn(NO₃)₂.4H₂O zinc nitrate (3.00 mmol, Merck, 98.5%), and 0.554 g of NH₂-BDC 2-amino-1,4-benzenedicarboxylic acid (3.03 mmol, Alfa Aesar, 99%) are dissolved in 75 ml of dimethylformamide (DMF, Aldrich, 99.8%). 0.542 g of 1,4-diazabicyclo[2.2.2]octane DABCO (4.815 mmol, Aldrich, 98%) is next added to the solution. This addition is reflected by the immediate appearance of a white precipitate. The precipitate that is obtained is filtered on low-porosity sintered [sic] while the filtrate is recovered and diluted with 75 ml of DMF. The solution that consists of filtrate is next divided into 5 aliquots of 30 ml that are distributed into 5 stainless steel autoclaves (43 ml capacity) and heated from 35 to 120° C. with a slope of 2.5° C/minute. The temperature is maintained at 120° C. for 12 hours. This operating mode makes it possible to obtain yellowish crystals in the form of DMOF-1-NH₂ rods. The mother liquor is allowed to decant, and the crystals are washed three times with 6 ml of DMF, and then three times with 6 ml of CH₂Cl₂ (Acros Organics, 99.99%). Next, the crystals are left in suspension in 10 ml of CH₂Cl₂ for 3 days, with a renewal of solvent every 24 hours. Finally, the crystals are dried under vacuum at ambient temperature for one night. 300 mg of DMOF-1-NH₂ is thus obtained or a yield of 35% based on the initial Zn(NO₃)₂.4H₂O.

Said DMOF-1-NH₂ crystallized hybrid solid is analyzed by X-ray diffraction, by Fourier Transform Infrared spectroscopy, and by nuclear magnetic resonance of hydrogen (¹H NMR).

The X-ray diffraction analysis reveals that said solid that is obtained in Example 1 is identified as consisting of DMOF-1-NH₂ solid: the diffractogram that is implemented on said solid is identical to the one that is presented in Inorganic Chemistry, 2009, 48, 300.

The FT-IR analysis reveals the presence of the —NH₂ amino group in the DMOF-1-NH₂ IR (KBr pellet) solid, ν (cm⁻¹): 3454, 3344, 2958, 1632, 1666, 1577, 1435, 1376, 1256, 1056, 833, 810, 772, 704, 661, 593. The bands at 3454 and 3344 cm⁻¹ are attributed to the amine group.

The ¹H-NMR analysis is implemented on a sample of the DMOF-1-NH₂ solid, after total digestion and dissolution of the sample in a DCl/D₂O/DMSO-d₆ deuterated mixture according to the operating mode that is described in the literature (Z. Q. Wang, S. M. Cohen, Journal of the American Society, 2007, 129, 12368-12369): 10 mg of DMOF-1-NH₂ hybrid solid is digested and dissolved in 1.5 ml of deuterated DMSO and 0.2 ml of a dilute DCl solution (prepared from a solution that contains 0.23 ml of DCl/D₂O at 35% and 1 ml of deuterated DMSO).

The ¹H-NMR analysis also reveals the presence of the —NH₂ amino group in the DMOF-1-NH₂ solid. ¹H NMR, 250 Hz, t.a, δ (ppm/(DCl/D₂O/DMSO-d₆)): 7.02 (d, 1H, J=8.3 Hz); 7.38 (s, 1H); 7.74 (d, 1H, J=8.3 Hz), 3.52 (s, 6H, DABCO).

The ¹H-NMR analysis also makes it possible to confirm the presence of the NH₂-bdc and DABCO ligands in a proportion such that the NH₂-bdc/DABCO molar ratio=2.

Example 2 Preparation of the DMOF-1-N₃ Solid by Post-Modification of the DMOF-1-NH₂ Hybrid Solid

80 mg (0.27 mmol equivalent of —NH₂) of dried DMOF-1-NH₂ solid, obtained at the end of the process that is illustrated in Example 1, is placed in a flask (10 ml capacity) with 3 ml (37 mmol) of THF, 0.217 ml (1.84 mmol) of tBuONO (Aldrich), and 0.199 ml (1.508 mmol) of TMS-N₃ (Aldrich). After 12 hours of reaction at ambient temperature, the solid is filtered and then washed three times with 6 ml of THF (Carlo Erba), and then three times with 6 ml of CH₂Cl₂ before being dried under vacuum at ambient temperature.

The solid that is obtained has been analyzed by X-ray diffraction and identified as consisting of DMOF-1-N₃ crystallized hybrid solid: the diffractogram that is implemented on the DMOF-1-N₃ solid is the one that is provided by FIG. 1. The analysis that is implemented on the DMOF-1-N₃ crystallized hybrid solid by XRD demonstrates that the post-modification treatment that makes it possible to substitute the —NH₂ amino group by the —N₃ azide group does not affect the structure and the crystallinity of the solid.

The FT-IR analysis reveals the presence of the —N₃ azide group on each of the terephthalate ligands in the DMOF-1-N₃ solid. The spectrum that is obtained by FT-IR has a characteristic band of the azide group at 2123 cm⁻¹. The bands at 3454 and 3344 cm⁻¹ that correspond to the —NH₂ group have disappeared.

The ¹H-NMR analysis is implemented on a sample of the DMOF-1-N₃ hybrid solid, after total digestion and dissolution of the sample in a DCl/D₂O/DMSO-d₆ deuterated mixture according to an operating mode that is described in the literature (Z. Q. Wang, S. M. Cohen, Journal of the American Chemical Society, 2007, 129, 12368-12369): 10 mg of DMOF-1-N₃ hybrid solid is digested and dissolved in 1.5 ml of deuterated DMSO and 0.2 ml of a dilute DCl solution (prepared from a solution that contains 0.23 ml of DCl/D₂O at 35% and 1 ml of deuterated DMSO).

The ¹H-NMR analysis confirms the presence of the N₃ azide group in the aromatic cycle of the deprotonated terephthalic ligand. ¹H NMR, 250 Hz, t.a, δ (ppm/(DCl/D₂O/DMSO-d₆)): δ=7.74-7.85 ppm, m, 3H, ArH. The 3 protons that lead to the detection of the multiplet correspond to 3 protons that are carried by the aromatic cycle of the 2-azido-terephthalate (N₃-bdc) ligand.

The comparison of the IR and ¹H-NMR spectra that are obtained for the DMOF-1-NH₂ solid and for the DMOF-1-N₃ solid demonstrates the effectiveness of said post-modification treatment, the comparison of ¹H-NMR spectra obtained for the DMOF-1-NH₂ solid and for the DMOF-1-N₃ solid that make it possible to estimate at 98% the rate of modification of the amino groups into N₃ azide groups, by quantifying the decrease of the relative area of the signals of the DMOF-1-NH₂ compound relative to those of the DMOF-1-N₃ compound. 

The invention claims is:
 1. A crystallized hybrid solid having a three-dimensional organic-inorganic matrix represented by the formula: DMOF-1-N₃, which comprises an inorganic network of zinc metal centers connected to each other by an organic ligand represented by the formula:

and an organic ligand represented by the formula:

wherein the crystallized hybrid solid has a chemical composition having the following base pattern: Zn₂(—O₂C—C₆H₃—N₃—CO₂—)₂(C₆H₁₂N₂), and further wherein the crystallized hybrid solid is characterized by an X-ray diffraction diagram comprising at least the lines in the table below: 2 Thêta (°) d_(hkl) (Å) I/I₀ 8.152 10.837643 F 9.19 9.615264 mf 11.538 7.663371 mf 12.296 7.192531 mf 14.77 5.992845 ff 16.345 5.418821 FF 18.29 4.846741 f 18.44 4.807632 ff 18.782 4.720763 f 20.19 4.394638 ff 20.504 4.327992 ff 21.806 4.072553 ff 23.195 3.831685 ff 24.623 3.612547 f 24.737 3.596266 ff 24.996 3.559468 ff 25.978 3.427163 ff 26.086 3.413252 ff 26.333 3.381744 ff 27.609 3.228232 ff 27.813 3.205088 ff 29.029 3.0735 f 29.698 3.005821 ff 29.793 2.996423 ff 30.201 2.956894 ff 30.938 2.888069 ff 31.15 2.868907 ff 32.046 2.790679 ff 32.428 2.758663 ff 33.035 2.709411 ff 33.492 2.673413 ff 34.082 2.628514 ff 34.36 2.607855 ff 35.102 2.554457 ff 35.184 2.548681 ff 35.373 2.535482 ff 36.361 2.468819 ff 36.52 2.458421 ff, where FF = very high; F = high; m = medium; mf = medium low; f = low; ff = very low, with the relative intensity I/I_(o) being provided relative to a relative intensity scale where a value of 100 is assigned to the most intense line of the X-ray diffraction diagram: ff < 15; 15 ≦ f < 30; 30 ≦ mf < 50; 50 ≦ m < 65; 65 ≦ F < 85; and FF ≧ 85.”


2. The crystallized hybrid solid according to claim 1, wherein the crystallized hybrid solid has a crystalline structure identical to a DMOF-1-NH₂ crystallized hybrid solid, with the exception that the —NH₂ groups of the DMOF-1-NH₂ crystallized hybrid solid are replaced by —N₃ groups.
 3. The crystallized hybrid solid according to claim 1, wherein each zinc atom is surrounded by four oxygen atoms obtained from four equatorial N₃-benzene-1,4-dicarboxylate ligands and a nitrogen atom obtained from an apical 1,4-diazabicyclo[2.2.2]octane ligand.
 4. A process for the preparation of a crystallized hybrid solid according to claim 1, comprising: i) reacting a crystallized hybrid solid represented by the formula: DMOF-1-NH₂, with a compound represented by the formula: R-NO₂, wherein R is selected from the group consisting of sodium and tert-butyl, and a compound represented by the formula: Q-N₃, wherein Q is selected from the group consisting of sodium, trimethylsilyl, toluenesulfonyl and trifluoromethanesulfonyl, in the presence of a polar solvent, S, at a temperature between 0° C. and 100° C. for a period between 1 and 24 hours, and further wherein the reaction mixture has the following molar composition: 1 DMOF-1-NH₂:3-12 R—NO₂:1-9 Q-N₃:100-400 S; and ii) drying the crystallized hybrid solid represented by the formula: DMOF-1-N₃.
 5. The process according to claim 4, wherein the crystallized hybrid solid represented by the formula, DMOF-1-NH₂, is dried prior to addition to the polar solvent, S.
 6. The process according to claim 4, wherein Q in the compound represented by the formula, Q-N₃, is trimethylsilyl.
 7. The process according to claim 4, wherein R in the compound represented by the formula, R—NO₂, is tert-butyl.
 8. The process according to claim 4, wherein the polar solvent, S, is selected from the group consisting of tetrahydrofuran and acetonitrile.
 9. The process according to claim 4, wherein the reaction mixture has the following molar composition: 1 DMOF-1-NH₂:5-7 R—NO₂:5-8 Q-N₃:100-200 S.
 10. The process according to claim 4, wherein the reaction is performed at ambient temperature.
 11. The process according to claim 4, wherein the reaction is performed for a period between 5 and 15 hours. 